Use of a blanket tungsten chemical vapor deposition (W-CVD) for contact hole filling has increasingly gained attention in recent years because of its resultant superior step coverage and low resistivity in ultra large scale integration (ULSI) technology. However, the adhesion of a tungsten film to other insulating film, such as a silicon oxide film, a phosphosilicate glass (PSG) film, or a borophosphosilicate glass (BPSG) film, is extremely poor. Therefore, TiN or TiW film has been utilized as an adhesive layer to overcome this disadvantage. Relevant documents may be found in the following references: D. C. Smith, Proc. 2nd Int. Conf. IEEE VLSI 1985 (IEEE, New York, 1985) P.350; Hee-Seok Choi and Shi-Woo Rhee, J. Electrochem. Soc, 141, 475 (1994); Nathan Desatink and Brian E. Thompson, ibid., 141, 3532 (1994); Pei-lng Lee, John Cronin, and Carter Kaanta, ibid., 136, 2108 (1989); J. E. J. Schmitz, Chemical Vapor Deposition of Tungsten and Tungsten Silicides (Noyes, Ridge Park, N.J., 1992); R. V. Joshi, D. Moy, S. Brodsky, A. Charai, L. Krusin-Elbaum, P. J. Restle, T. N. Nguyen, and C. S. Oh, Appl. Phys. Lett. 54, 1672 (1989); and K. Suguro, Y. Nakasaki, S. Shima, T. Yoshii, T. Moriya, and H. Tango, J. Appl. Phys., 62, 1265 (1987).
The adhesive layer TiN is usually formed by a rapid thermal nitridation (RTN) of a sputtered Ti film, where the Ti sputter system uses a 2 mm clamp ring around the wafer edge. If a tungsten film is deposited onto this specific ring area where BPSG exists, peeling of the tungsten film usually occurs. To avoid this problem, a W-CVD chamber has been equipped with a 5 mm shadow ring. However, formation of nucleation is not totally completed under the shadow ring area. During a later step of CVD tungsten bulk deposition, the remaining WF.sub.6(g) penetrates the RTN-TiN barrier layer and further reacts with the underlying Ti residual, forming some cone shaped TiFx.sub.(g) bubbles. Hence, the volcanic formation occurs at the W/TiN boundary, causing particle contamination and device failure.